Since someone else /cast Raise Dead on this thread, I'll chime in with my shiny bits.
I dealt with almost this SPECIFIC situation myself, only instead of asking to come back to the guild, he attempted to poach me after my ex wife/gm and I split up. I have no problem with him as a person anymore, because he's legitimately tried to better himself. He quit drinking which made him much more personable, and we talk on the phone about once every three months.
I would allow him to form his raid team, assuming he either filled it from the lesser utilized members of the current bench or recruited his own raiders to join the guild/team. The latter way, he could form his own ten player group, and farm some lower level raids to get them in sync with each other before tackling current xpac content, which would help your guild grow in the end (assuming you aren't level 25 yet). However, until he'd shown that he could effectively lead his team without being a general dick to be people in sneaks (raid chat, whispers, etc.) for quite a while, there's no way he would make officer, and when he did, he would have his own rank of Raid Leader (Team Designation - I recommend using non-sequential terms for this to prevent terminology drama) that had little control over the general function of the guild. Just the ability to make calendar events for his team and see officer chat.
Even when I'd had planned absences from the game for any extended duration, I took my duties as an officer very seriously. Despite my wow account being cancelled for a couple months, I still interacted with the guild over vent or really any method of communication I had available, including facebook and even AIM. My role shifted from essentially second in command to "the smart guy." My job was to farm every available scrap of data that might help our members, from leveling specs to raid specs, rotations, glyphs, gear, or to be the impartial listener/moderator that solved member issues. Even without logging into the game once within a 2 month period on my own account (I toyed around with my ex's alts on occasion, and played my own toons on her account on other servers while she slept), I still made it a point to interact daily. If he isn't that dedicated to the guild, I wouldn't give him an officer position in the first place.
The examples given are obviously from my own experience, but they're also for a very laid back guild that just raided "to kill time and maybe a few bosses." Thus, if your guild is more dedicated to raiding than just flapping gums in guild chat, I think I'm definitely on the right track.
I'm way better at holding my liquor than a panda.